1. Field of the Invention
The present invention relates to a light distribution control system for a vehicle headlamp and, in particular, to a light distribution control system for a headlamp for driving with an adaptive front-lighting system.
2. Description of the Related Art
Conventionally, in a light distribution control system for a vehicle headlamp, there has been known a method of switching various light distribution patterns in accordance to a state forward of a vehicle (for example, Japanese Unexamined Patent Application Publication No. 2011-255826 and Japanese Unexamined Patent Application Publication No. 2011-238378). Such a light distribution control system is provided with a light distribution pattern configured to irradiate a distant area, a light distribution pattern configured to irradiate a nearby area in terms of prevention of a glare given to other vehicles (for example, an oncoming vehicle), and the like. These light distributions may be formed independently by individual radiating portions prepared for respective light distribution patterns, or may be formed by forming one light distribution pattern by a predetermined radiating portion, forming another distribution pattern by another radiating portion by complementing a difference from the aforementioned distribution pattern, and synthesizing these patterns.
In these light distribution patterns, in order to achieve both reduction of glare and improvement of visual recognition, a light distribution pattern configured to shade a part where other vehicle exists has been known. In such a light distribution pattern, there has been known a method in which a light distribution pattern is tilted in the horizontal direction of the vehicle by rotating a radiating portion in the horizontal direction from the front side of the vehicle in accordance with the approach of an oncoming vehicle. Accordingly, both reduction of glare and improvement of visual recognition are achieved more effectively.
However, in the vehicle headlamp provided with such rotating-type radiating portions, due to limitation of layout for space saving or the like, only necessary radiating portion is configured in a rotatable manner while other radiating portion is fixedly arranged. Therefore, in a case of switching from a light distribution pattern by a radiating portion rotated in the horizontal direction of the vehicle to a light distribution pattern by other radiating portion, a radiating direction of a light distribution pattern could be greatly changed between before and after switching. In such a case, there is the possibility of giving a feeling of discomfort to a user due to great displacement caused to the high-intensity point within his or her visually-recognizable range.